1. Field of the Invention
The present invention relates to an image processing apparatus, a method of controlling the same, and a storage medium.
2. Description of the Related Art
Recently, on fears of world-wide shortage of energy resources, utilization of natural energy has been rapidly pursued. One of the most potential natural energy resources is solar cells. Power generated by solar cells is DC power, and a storage battery for storing the power is also a DC battery. Further, many of electrical appliances are driven by DC power obtained by converting commercial AC power. If DC power generated e.g. by solar cells is used without being converted to AC power, power usage efficiency can be enhanced.
For this reason, a home hybrid power system that supplies power using two systems, i.e. a direct current (DC) system and an alternating current (AC) system, is under development. In the development of such an AC/DC hybrid power supply system, it is envisaged that electrical appliances which can be used at low voltages are supplied with power by the DC system, and a refrigerator and the like which need high voltages are supplied with power by the AC system.
For nighttime DC power supply, the AC/DC hybrid power supply system is provided with a storage battery that is charged with power during daytime and an AC-to-DC converter that converts AC power to DC power. Further, some AC/DC hybrid power supply systems are provided with a DC-to-AC converter that converts DC power to AC power for selling power.
In connection with the above-mentioned technique, there has been disclosed a power management method for an image processing apparatus using USB supply power and a battery (see e.g. Japanese Patent Laid-Open Publication No. 2011-061974).
According to the disclosed method, DC power is generated from commercial AC power and USB supply power and is supplied to each of components requiring power. Further, the DC power is used to charge a built-in rechargeable secondary battery. The voltage of each power supply is detected, and when it is judged, based on an operation mode of a copying machine and a result of the voltage detection, that sufficient power cannot be supplied from the USB supply power alone, power from the recharged secondary battery is supplementarily supplied.
Since the USB supply power is DC power, Japanese Patent Laid-Open Publication No. 2011-061974 proposes the image processing apparatus that is operated using a commercial AC power supply and a DC power supply as power supply sources.
However, to supply power from the secondary battery to a component which requires a large amount of power, such as a fixing section of an image forming apparatus, by the method proposed in Japanese Patent Laid-Open Publication No. 2011-061974, the secondary battery is required to have a very large capacity and hence is very expensive.
On the other hand, in the AC/DC hybrid power supply system, although the commercial AC power supply is capable of supplying a large amount of power and is stable, the DC power supply is not capable of supplying a large amount of power and is low in stability.